Relay



V. A. LEACH June 24, 1941.

RELAY Filed ot. 2o, 1959 /NVe/VTOR 144A A. Lm cH A Ww. F: N

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Patented June 24, 1941 UNITED STATES TENT FFICE 1I Claims.

My invention relates to electrical control devices in general, and to relays in particular.

The essential elements of a conventional relay include a contactor switch for a main circuit and electromagnetic means to control the contactor switch in response to energz'ation of an auxiliary circuit. The contactor switch is yieldingly urged in one direction toward one of its two stationary positions, usually by spring means, and is moved in the opposite direction toward its other stationary position by electromagnetic means in opposition to the yielding means. In many installations such relays are exposed to incidental forces that either act on the contactor switch directly or act on the movable parts of the electromagnetic means to shift the contact switch from one of its stationary positions to the other in opposition to the yielding means. In other words, mechanical forces originating outside the relay may, at least momentarily, operate the relay in the same manner as would result from closing of the auxiliary circuit through the relay.

In some instances of uncontrolled operation some object accidentally strikes the movable contactor switch, but in most instances of inadvertent operation the actuating force arises from bodily movement of the relay as a whole. Thus, a relay mounted on machinery may be operated by excessive vibration, and a relay carried by a vehicle may be operatively affected by acceleration, deceleration, or sudden change in direction of travel on the part of the vehicle. Such uncontrolled and unpredictable action is usually highly undesirable, especially ifvthe relay has some important role, and in some installations may involve a serious hazard. A relay having an important function in the operation of an airplane, for example, may in the normal course of flying be subject to such vibration, shock, acceleration, or deceleration as to cause it to operate abnormally at critical moments.

It is possible, of course, to reduce this hazard by employing a yielding means of such strength as to resist incidental forces of normal magnitude acting on the contactor switch, but there are disadvantages in relying on such an expedient. In the rst place, positive prevention is not achieved because there is the possibility of some force of abnormal magnitude overcoming any spring that may `be used, and, in the second place, increasing the strength of the spring increases the demand on the electromagnetic means.

The general object of my invention is to provide a relay of simple but highly eiiicient construction that will function in a controlled and dependable manner in; the face of such external forces. In the preferred form of my invention disclosed herein, it is my purpose in attaining this general object to provide a positive means for immobilizing the contactor switch when the yelectromagnetic means is de-energized, and further, to make the moving parts of the electromagnetic means immune to the external forces.

With reference to immobilizing the contactor switch, my invention is characterized by the conception of providing a lock that normally blocks movement of the contactor switch but automatically releases the contactor switch whenever the electromagnetic means is energized.

In the preferred form of my invention I propose to operate both the lock and the contactor switch by the electromagnetic means. More specifically, I contemplate operating the relay by electromagnetic means in which a movable armature is adapted to serve both as actuator and locflr for the contactor switch.

A further object in mind is to operatively interconnect an electromagnet armature and a contactor switch by means that is irreversible in the sense that it permits the armature to move the contactor switch but locks the contactor switch against transmitting movement to the armature.

With reference to making the movable parts of the electromagnet immune to forces that arise from bodily movements of the relay, my invention is characterized by the concept of pivotally mounting an armature in static balance about its pivot axis so that all forces caused by inertia of the armature mass pass through the pivot axis, no moments about the pivot axis being created. Thus, by blocking the contactor switch with a lock operated by the armature, and then balancing the armature statically, I completely safeguard the relay from operation by vibration, shock or bodily acceleration of the relay.

Those skilled in the art will appreciate from the foregoing that my invention may be embodied in diverse relays for various iields of application. The fact, then, that for the purpose of the present disclosure I elect to describe in speciiic detail a small relay suitable for aircraft circuits, is not to be taken as limiting the scope of my invention.

The above and other objects and advantages of the invention will be apparent in my detailed description to follow, taken with the accompanying drawing. Y

In the drawing:

Fig. 1 is a side elevation of a preferred form of my relay suitable for use in aircraft;

Fig. 2 is a front elevation taken as indicated by the arrow 2 in Fig. 1, the front plate of the relay being removed to reveal the interior mechanism;

Fig. 3 is a transverse section taken as indicated by the line 3--3 of Fig. 1;

Fig. 4 is a longitudinal section taken as indicated by the line lil-l of Fig. 2; and

Fig. 5 is a view on a greatly enlarged scale of the lock means employed in the relay.

The relay mechanism is mounted in a frame generally designated Iii, which maybe fabricated from a single` sheet of non-magnetic metal bent to form side plates and I2 vinterconnected Yby a bottomplate i3. The two side plates 'il and|2 provide inwardly turned ears ifi to receive screws l5 fcr'retaining a front plate or .terminal block l5 of insulating material and in `'like manner at the opposite end of the frame ears-I8 are provided to receive screws 9 for retaining a rear plate or terminal block of .non-conducting material.

A contacter switch generally designated 22 may include a'metal plate 23 that is pivotally mounted on' a hinge pin 24 byv'ears 25, the-hinge pinin turn being mounted in suitable bores in ythe Vside plates Hand i2 and being provided at each end with a Awasher 2S and a cotter pin 2l.

Oneof the ears 25 of the-plate 23 may be extended as an arin'SG, the lower end of whichis connected to a forward point of the frame I5 by a helical spring 3|. It is apparent that the arm 33, together with the plate 23, forms a bellcrank, and that the force of the spring 3| tends yto swing the forward end of the plate23 upward Vabout the hinge pin-24 as an axis.

One or more switch lingers, preferably of flexible metal, may be mounted on-and'insulated from the plate 23 to `cooperate in kopening and closing one or more main circuits when the VplateV 23 isfoscillated. In Vthe particular relay shown in the drawing, I provide three such switch ngersf33 securedV by rivets 3d to an insulating Vblocleli that is in turn attached to the plate 23 by suitable screws 33. Each ofthe switch fingers-33 is connected by an insulationcovered wire 31 with va corresponding'terminal clip-38-on the rear terminal block 2i). lThe Yfor- Ward ends of the switch fingers 33 are adapted to cooperate Vwith stationary contacts of the main circuit or circuits.

In the particular construction'shown, each of the Iswitch fingers 33 carries an upper.l contact 40 and a lower contact 4|, which maybe referred to as the movable contactsof the relay. Above each of the upper contacts 4G is astationaryV contact-,42 on a contact arm 43 that is integral with a terminalzclip M. carried bythe front terminal block |6. In like mannerzbelow each'lower contact 3| isa stationary conta-ct L55 on a contact arm 45 that is mounted onthe i6 and terminates in a One of the stationary posifront terminal block: terminal clip 41.

tions of the contacter switch 22 is an upper posidescribed arrangement the spring 3| urges the aaeavso contactor switch to the upper position, but the spring may be disposed in the opposite direction to urge the contactor switch to the other position, if required'. One of these sets o-f stationary contacts i2 and 45 may, of course, be dead or be omitted entirely in installations where the function of the contacter switch is simply to open and close a main circuit.

In various'practices within the scope of my ifi invention various electromagnetic arrangements may be employed to move the icontactor switch `22 from one of its stationary positions to the other against the resistance of the yielding means that i-s exempliiied by the helical spring if, 3|. In the present illustrative arrangement an ielectrorna'gnet coil 5|) having a core 5| is disfposed transversely of the relay frame Iii, there being a pole piece 52 in the form of a lat bar Vattached to each end of the core 5|. 2c. 53 is connected to each ofthe side plates of the frameli) byf-a-suitable screw 53 opposite the core I5 v and i by a second f forwardly spaced screw 5d interconnecting the side plate of the frame andthe corresponding -pole piece 52. lThe elec- 25 tromagnet ycoil 5i! is adapted tube-connected to anauxiliary or controlling circuit through the medium ofapair of insulation covered wires4 55 that connect with corresponding terminal Clips 15B on the rear terminal-blcckRl.

The ends-of the two polepieces 52 are bent inward toward each other to form two opposed poles v5d and 59 having opposed larcuate faces and Aiii respectively. rAn armature 33 is .adapted to respond to energization of the `coil 323 5libyrotating about an axis approximately midway between the two poles 58 and 53. For mounting the :armature to oscillate in the. desired manner, I may `provide a cross-plate .64 slightly forward of the planeA of the polesV 53 and 40 59, Ythe .cross-plate being attached by suitable screws E5 to ears-66 on theside plates of the frame l. Rearward of the Yplaneof the two A-poles 58 :and 53 lI .may Yprovide Van upwardly turned tongue 6l cut from the bottom plate I3 J5 ofthe frameto-'serve as-.abracket spaced rearward from.V the cross-plater. By virtue ofthis arrangementlfmaymount the-armature S3 on a-pivot. pin 33 thatpasses through suitable Vbores in the cross-plate. Si and the tongues '67, the dra-wingshowinga spacing washer E9 between the armature and the Aupwardly turned tongue. `Thearcuatefacciali ofthel pole-58 is eccentric withrespect to the pivotal axis of the armature "63, 4the center :of curvature of the face being above that axis, while the facel of the pole59 is alsoveccentric with respect to the armature Yaxis with the center of curvature belowthat axis. The-twoY endsof the armature havearcurate faces 'ill and 7| corresponding to the'pole 60 faces 60 and v6i respectively, the curvature of each armatureface being `complernentaryto the curvature of the corresponding pele 4face,-and thearmaturefbeing dimensioned to place'its end facesrelatively close to the pole faces when the energiZation-of the coil 50 causes the armature to take a position longitudinally aligned with Jthe Vtwo polea-the -positionfshown in-dash-dot `lines=in Fig.f3. It'is apparent that, as viewed Yin7'l'ig-3, theindicated eccentricity of the complementaryfaces of the armatureandthe two poles-results in relatively little increase inthe ,gap.between the pairs of complementary'faces f as the armature rotates from its energized posi- Y tiontoits.de-energiZed-position that is shown'in fun lines inrigja "n will be noted that'inng.

The coil y 3 the lower end of the armature face 'l0 at the de-energized position is in .close proximity to the corresponding pole face 60 and likewise the upper end of the armature face l'l is in close proximity to the complementary pole face 6l. The indicated coniigurations of the poles and ythe armature favor effective magnetic action to rotate the armature out of its de-energized position, not only because of the relatively narrow air gaps at .the de-energized position of the armature, but also because each of the poles, in effect, overhangs an end of the armature in a manner that increases the effectiveness of the magnetic coupling when the coil D is energized.

To urge the armature towards its normal deenergized position the armature may be provided with a downwardly extending integral lug 74 that is apertured for engagement by one end of a helical spring 15, the spring 'I5 being connected to the side plate Il of the frame.

The contactor switch 22 may be adapted for operative connection to the armature 33 in any suitable manner and any suitable means may be employed for the operative connection. In the particular construction shown a forward extension 'l1 of the plate 23 is bent downwardly to form a tongue "it above the armature t3. The lower end of the tongue i8 is of reduced width and terminates in an inwardly turned iiange 56. A connector plate 8i for linking the contactor switch 22 to the armature d3 is slidingly mounted between the armature and the cross-plate iid, the connector plate having a iinger 32 at its upper end engaging a complementary aperture 33 in the tongue 'i8 and having a second finger E-l at its lower end engaging the bottom edge of the armature to one side of the armature axis. The connector plate 8l has a guide slot 85 engaging the armature pivot pin G8, and preferably spacers in the form of thin washers B are mounted on the pivot pin on opposite sides oi the connector plate.

Normally the sprnig 3i acting on the arm ISG holds the contactor switch in its uppermost position with the upper movable contacts lib pressed against the upper stationary contacts d2, and the spring '15 normally holds the armature 53 rotated to its normal inclined or cie-energized position, the various parts of the mechanism having the positions indicated in full lines in all the figures of the drawing. When energization of the electromagnet coil 55 setting up magnetic ux between the poles 58 and $9 causes the arma- 'ture 63 to rotate counter-clockwise to its substantially horizontal energized position, the lower edge of the armature moving against the lower finger 84 of the connector plate Si shifts the connecior plate downward, and since the upper finger 82 of the connector plate engages the tongue i8, the contactor switch follows the downward movement of the connector plate. As the armature approaches its horizontal energized position, the lower movable contacts di of the contactor switch move against the corresponding lower stationary contacts 45, the various parts of the mechanism then taking the position shown in dot-dash lines in Figs. 3 and i.

Various locking arrangements may be emplo-yed to block movement of the contactor switch when the electromagnet is cle-energized. The preferred form of my invention is characterized, however, by an exceedingly simple construction in which the lock consists of an upwardly extending stop lug 88 on the armature 63, the stop lug 8 is so constructed and arranged that when the armature E53 is in its deenergized position the stop lug blocks the path of downward movement of the contactor switch, but immediately moves clear of the path when movement of the armature from its de-energized position to its energized position is initiated. The drawing shows the lug 88 with a notch i for engagement with the lower end of the tongue '13. In the normal de-energized position of the armature 63, one face il of the notch, as best shown in Fig. 5, rests against the lower edge of the tongue 'i3 and against the edge ofthe flange 8G of the tongue, thereby limiting the extent to which the armature 53 may be rotated clockwise by the spring l5. At the same time a second face 9i formed by the notch 8S extends into the path through which the lower end of the tongue I8 must move if the contactor switch is to shift downward suiiiciently to carry the lower movable contacts il against the lower stationary contacts dii. There is normally appreciable clearance between the face Si and the lower end of the tongue i8 to insure freedom of Inovement of the stop lug 53 into and out o1" the normal position o 5, but the clearance is not sufficient to oier any possibility of the contactor switch reaching its lower operative position while the stop lug is in blocking position.

It is apparent that the lock arrangement described aiords positive protection against external forces acting on the contactor switch tending to shift the contactor switch to its lower position. For complete protection it is necessary also to make the armature 63 immune to forces arising from inertia of the armature when the relay is moved bodily as heretofore pointed out. For this purpose the armature 53 is of substantially uniform thickness and is substantially symmetrical about the axis oi the armature pivot pin 58. More specifically, it will be noted that the armature body as defined by the straight lines of its longitudinal edges is statically balanced about the axis of the pivot pin and that the lower lug 'id is both diametrically opposite from the upper stop lug t3 and substantially equal in mass to the upper stop lug. lThe relay may be vibrated or jolted bodily in any direction, then, without operative eiect on either the contactor switch or the armature.

The preferred form of my invention described in specific detail herein will suggest to those skilled in the art various changes, modiiications, and substitutions that may be made without departing from my underlying concept, and I reserve the right to all such changes, modications, and substitutions that properly come within the scope of my appended claims.

I claim as my invention:

l. In a relay, the combination, of: a main-circuit contactor switch movable from a first switch position to a second switch position and vice versa; an auxiliary-circuit electromagnet; a pivoted armature operatively connected to said contactor switch and movable from a first armature position to a second armature position to move said contactor switch from said rst switch position to said second switch position in response to energization of said electromagnet, said armature being biased to return to said rst armature position when said electromagnet is de-energized, said armature being in substantial static balance about its pivot axis to prevent operative turning moments about said axis from inertia of the armature when the relay ismoved bodily byex- -ternalforces while said .electromagnet is de- -..energized; and locking means eiiective to hold :said contactor switch in said first switch v'posi- :tion against external forces when said electro- 'lmagnet is `de-energized and to release said contactor switch automatically when said electromagnet is energized.

`2.,.In a relay a combination as set forth in claim l in which both said contactor switch and.

said locking means are operatively connected to saidarmature.

3. In a relay, the combination oi: a main- Ycircuit ycontactor switch movable from .a first fswitchposition to a second switch position and =vice versa; an .auxiliary-circuit electromagnet; an'armature operatively connected to said contactor switch and movable from a rst armature position toia second armature position to move said contactor switch from said ,rst switch po- -sition tosaidlsecond switch position in response 'to energization of said electromagnet; and a stop Ymeansfmounted on and unitary with said arma- A-ture .and ,positioned to be carried therebyinto aposition blocking movement of said contactor .switch `from said `iirst switch .position of the .contacto-r switch when said electromagnet is deenergized.

4. In a relay, the combination of: a maincircuit contactor yswitch movable from a first `switch position to a second switch position and vice versa; an auxiliary-circuit electromagnet; an'armature operatively connected to said contactor switch and movable from a i'lrst armature -position to a second armature position to move4 said contactor switch from said rst switch position to said second switch position in resp-onse to energization of said electromagnet; and stop .means unitary with said armature and positioned to be carried thereby into the path of movement `ofsaid contactor switch when said electromagnet is de-energized, there being normal clearance between said stop means and said contactor switch `suiiicient to permit freedom of movement on the part of said armature but not suilicient to permit said contactor switch to reach said second switchzposition when the electromagnet is deenergized.

-5. In a relay a combination as set forth in claim 3 in which said armature is pivoted to rotate about an axis and in whichV said stop means in its blocking position is so aligned with the axis of the armature pivot that blocking force is directed radially of the pivot axis and therefore creates no turning moment on the armature.

'6. In a relay a combination as set forth in claim 3 in which said armature is pivotally mounted to rotate about a pivot axis and is statically balanced with respect to that axis, in which said stop means in its blocking position is so aligned with the axis of the armature pivot vthat vvblocking force is directed radially of the pivotaxis and therefore creates no turning movment on the armature.

v'7.'In-a relay, the combination of: a maincircuit contactor switch movable from a first switch position toa second switch position and YVice versa; an'auxiliary-circuit electromagnet; '-a 'pi-voted armature operatively connected to said Vcontactor switch and rotatable from a rst armature position to-a secondarmature position to :move said `contactor switch from said rst :switchposition` to said second yswitch position in response to-energizationofsaid electromagnet; a

lprojection onsaidarrnature positioned to block vmovement of said contactor switch from'the first `switch position to the second switch position when said electromagnet is de-energized; a second projection on said armature; and yielding means connected to said secondprojectionto .urge-said armature to said iirst armature posiytion when said electromagnet is de-energized,

said armature being statically balancedwith said two projections diametrically cppositeeach other with respect to the pivot axis of the armature.

8. In a relay, the combination as set forth in claim 1 in which said electromagnet 'has ltwo .poles directed towardeach other and said pivoted armature is mounted between said poles, the'iace of one of said Apoles being arcuate and eccentric in one direction with respect to the axis of the armature, the face of the other pole being arcuate and eccentric in the opposite direction with respect to the axis oi said armature; and the corresponding surfaces of said armature being curved complementary to said pole faces.

9. In a relay, the combination of a contactor switch movable from a nrst position to a second position and vice versa; an auxiliary-circuit electromagnet; an armature pivotally mounted to rotate about an axis from a first armature position to afsecond armature position to move said contactor switch from said first switch position to said second switch position'in response to energization of said electromagnet; means oper- `atively interconnecting said armature and said contactor switch to transmit force from said armature .to said contactor switch, said interconnecting means being operatively movable toward and away from said armature axis; and means on said armature positioned to be carried by the armature to a point radially of said armature axis in said direction of movement of said interconnecting means to block movement of the interconnecting means when said electromagnet is cle-energized.

l0. In a relay, the combination as set forth in claim Qin which said armature is statically'balanced .with respect to its pivot axis to prevent rotation by inertia of the armature when the armature is moved bodily with the relay.

1.1. In a relay, the combination of: a contactor switch movable from ai'irst position to a second position and vice versa; yielding means urging said contactor switch to said rst position; an electromagnet; an armature operatively connected to said contactor switch, said armature being `responsive to said electromagnet to -move said contactor switch from its rst position to its second positionin response to energization of the electromagnet; and locking means movable between an ineiective position and an eiective position at which the locking means blocks movement of said contactor switch from the first position of the contactor switch to the second position oi the contactor. switch, said locking means being mechanically responsive to said armature to move automatically to its ineiective position upon initial movement of the armature in response to energization of the electromagnet.

VAL A. LEACH. 

